Our new anti-earthquake technology could protect cities from destruction

Broken homes Narendra Shrestha/EPA

Protecting cities from earthquakes is still a grand challenge that needs addressing, as recent disasters in Nepal, Japan, Haiti, and Chile confirm. Although significant progress has been made in understanding seismic activity and developing building technology, we still don’t have a satisfactory way of protecting buildings on a large scale.

For new buildings, anti-seismic technology is today considered quite advanced and it is possible to build individual structures that can withstand the vast majority of recorded earthquakes. Devices such isolation systems and dampers, which are designed to reduce the vibrations (and as a consequence the damage) of structures induced by earthquakes, are successfully employed in the design of new buildings.

But large numbers of buildings exist in earthquake zones that don’t have built-in protection, particularly in developing countries where replacing them or introducing stricter – and more expensive – building codes aren’t seen as an option. More than 130,000 houses were destroyed by the earthquake in Nepal in April 2015.

What’s more, these technologies are rarely used for protecting existing buildings, as they generally require substantial alteration of the original structure. In the case of heritage buildings, critical facilities or urban housing especially in developing countries, traditional localised solutions might be impractical.

This means there is a need for alternative solutions that protect multiple existing buildings without altering them using a single device. At the University of Brighton, we have designed a novel vibrating barrier (ViBa) to reduce the vibrations of nearby structures caused by an earthquake’s ground waves. The device would be buried in the soil and detached from surrounding buildings, and should be able to absorb a significant portion of the dynamic energy arising from the ground motion with a consequent reduction of seismic response (between 40-80%).

In need of protection. Narendra Shrestha/EPA

The idea behind this is to look at buildings as an integral part of a city model, which also includes the soil underneath and the interaction between each element, rather than as independent structures. Each ViBa can be designed to protect one or more buildings from an earthquake but also it forms part of a network of devices placed at strategic locations in order to protect entire cities.

The ViBa itself is essentially a box containing a solid central mass held in place by springs. These allow the mass to move back and forth and absorb the vibrations created by seismic waves. The entire structure is connected to the foundations of buildings through the soil to absorb vibrations from them. The box’s position underground would depend on how deep the surrounding foundations went and could even be placed on the surface.

As the ViBa is designed to reduce all vibrations in the soil, it could also be used to insulate buildings against ground waves from human activities such as road traffic, high-speed trains, large machinery, rock drilling and blasting. In this way, the technology would be able to absorb a larger quantity of energy than traditional measures used to insulate railways such as trenches or buried sheet-pile walls.

Starting construction

The problem with the ViBa is its size – it would need to be at least 50% of the mass of the average building it was protecting – and how much money it would cost to build and install as a result. So compared to current technologies to protect single buildings it would likely come with a much higher price tag. But as the ViBa can be designed to reduce the vibrations of more than one building or for buildings of historical importance for which current technologies are impractical, it can still be considered as a viable solution.

So far we have only modelled how the ViBa would work, using computers and prototypes in the lab. To be deployed in the real world we would need to do a lot more experimenting to understand exactly how it would work and to make sure it didn’t produce any damaging side-effects on the surrounding buildings. We would also need to work with industry to work out how to build and install it in the most cost-effective way.

But our latest research suggests the ViBa is a viable alternative strategy for protecting buildings from earthquakes. In the long term, it could lead to safer cities that are better equipped to deal with disasters and ultimately save lives.

That sinking feeling... could cavities on comet pose yet another risk to Philae?

Sinkholes on comet 67P could be a great thing for science -- but not if they they bury Philae. Vincent et al., Nature Publishing GroupVincent et al., Nature Publishing Group

Images of the surface of comet 67P/Churyumov-Gerasimenko have been decorating the front pages of newspapers and journals for the last few months. They have allowed us to see the full magnificence of the comets’ cratered terrain. Now a study suggests that these craters are actually sinkholes, created in a similar way to those on Earth when the surface layer of the ground suddenly collapses. While these pits could help us map the terrain of the comet, they could also pose a risk to the Philae spacecraft.

As the comet moves closer towards the sun, its activity has increased, leading to greater amounts of material from the exterior being turned into gas through the process of sublimation (where solid turns to a gas without first turning to liquid). It is clear, though, from the images of the navigation camera, that 67P is not equally active across all of its surface, and that jets of gas and dust can appear very quickly in sudden bursts of activity. This is not consistent with a gradual erosion of ice from across the comets’ surface as temperature increases.

The high resolution camera, OSIRIS, has shown panoramic images of craters, crevasses and valleys on the comet – including craters from which jets are emanating. That these are instead sinkholes is interesting but also slightly worrying, as such pits have the awkward habit of opening up in the most inconvenient of places at the most inconvenient of times.

The science of sinkholes

Sinkholes are caused when (usually) water washes away sub-surface rock and sediment, leaving a cap of material above a cavern. The cap can collapse at any time, becoming particularly vulnerable in times of increased rain or flooding.

More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. U.S. Geological Survey

The researchers believe that sinkhole formation on 67P may be a consequence of sudden collapse of a ceiling overlying a buried cavity. They speculate that the the cavities might have formed by collisions between metre-sized bodies at slow speeds, early in the Solar System’s history. Alternatively, they might be caused by sublimation of subsurface ice.

Whatever the cause of the underlying cavities, images from OSIRIS show that clusters of sinkholes with different depths and diameters across the surface of 67P. After the ceiling of a sinkhole has collapsed, fresh surfaces are exposed to solar radiation, following which jets form by sublimation of ice from the walls of the freshly opened hole.

Newly-formed, active sinkholes are deeper and have narrower diameters than ancient, dormant ones. If we could peer down into one of these holes, we would probably see layers of rock and ice, gradually becoming darker as more of the ice sublimated – leaving rock and dust behind. Dormant holes, on the other hand, seem to be filled in with debris, presumably of dust and rock from the sides of the hole which have collapsed.

Image of the most active pit, known as Seth_01. Vincent et al., Nature Publishing Group

What is intriguing about the sinkholes is the opportunity they provide to determine the regional geology and history of 67P’s surface. Sinkholes on similar terrain have similarly-sized holes. That means we can map the entire terrain of the comet based on the size of these pits. Similarly, the depth of sinkholes also matters. Since more shallow and debris-filled sinkholes tend to be older than deep ones, we can establish a chronology based on the depth.

What we all have to hope is that Philae is not perched precariously on the ceiling of one of these sub-surface cavities. It would be too cruel if the increasing sunlight, finally charging Philae’s batteries, also removed the ice supporting the lander, leaving sufficient power for Philae to broadcast its last message: “Help, I’m falling…”

Disclosure

Monica Grady receives funding from the STFC and is a Trustee of Lunar Mission One.

The secret to ovulation is in women's faces (but men can't see it)

Seeing red alixklingenberg/flickr, CC BY-NC

It’s not difficult to tell when a female chimpanzee is in heat. As she nears ovulation  — the point in her cycle when she’s most fertile  –  her bottom swells up like a balloon and turns bright pink.

Humans are obviously different. We don’t make a show of how fertile we are. But does this mean that women have evolved to conceal ovulation?

Women are most fertile during the late follicular phase of their menstrual cycle, which starts about a week after their period begins and ends a week later with ovulation. At this time, women experience subtle changes in their psychology, behaviour, and physiology that are akin to the changes we see in non-human primates.

You may have heard of Geoffrey Miller’s infamous lap-dancing study from 2007. Miller asked professional exotic dancers to keep a record of their nightly tip earnings for two months. The women also reported when their periods began and ended, so Miller could calculate when they were most fertile.

He found that the dancers received about US$67 (£42) per hour when they were near ovulation, but only US$52 (£33) at less fertile times of the month (and US$37 (£23) during their periods). This suggests that women are sufficiently more attractive at peak fertility to persuade men to part with their hard-earned cash. But why?

We don’t know for sure but it was probably a mix of signals. Research has shown that as ovulation approaches, women’s voices rise in pitch, their body odour becomes more sexually attractive, and they wear more revealing clothing.

The face of fertility

There is also some evidence that women’s faces are more attractive to both men and women near ovulation. The attractiveness effect is weaker when the women’s clothing and hair are obscured in the photograph. So clothing and hair are clearly important, but they’re not everything.

My research collaborators and I wondered whether womens' faces might be changing colour across the month. This isn’t as far-fetched as it sounds. Women’s attractiveness to men doesn’t vary over the cycle if the women are wearing make-up, which implies that make-up conceals natural changes in skin appearance. And other primates, such as rhesus and Japanese macaques and mandrills, develop a redder face when they’re most fertile.

Perhaps our own species experiences a similar – if less noticeable – change in facial redness. This could certainly explain the attractiveness effect: studies have found men rate women with redder faces more attractive.

The eyes have it. Olivier, CC BY-NC-SA

To find out, we photographed 22 young women volunteers on an average of 13 occasions and monitored where they were in their cycles, using a camera that replicated the images seen by the human eye. We asked them to avoid make-up and wear a black hairdressers’ smock so that the colour of their clothes wouldn’t be reflected onto their face (women are more likely to wear red or pink clothes when they’re fertile). Then we used a computer program to cut out patches of skin from the cheeks on each photograph.

We found women’s faces did change in redness over the cycle but not to a degree that could be seen by the human eye and therefore could not be detected by men, even unconsciously. Plus women are much more fertile just before ovulation than just after, but the redness of their faces at those two times was almost identical.

It is therefore pretty doubtful that facial skin colour is responsible for the effect of the menstrual cycle on women’s attractiveness to men. If our species ever advertised our fertility with noticeable changes in facial colour, we don’t any more.

Looking for more

It’s plausible that there are more obvious fluctuations in facial skin colour than those we detected. After all, we did only look at a small area of the cheek. Perhaps womens' lips becomes especially red at peak fertility, even without the help of lipstick (women wear more make-up near ovulation).

Some indicators of women’s fertility are stronger when women are more stimulated. Straight women are more flirtatious when fertile, but only in the presence of men they find attractive. Men find dilated pupils attractive in a woman, and heterosexual womens' pupils increase in diameter during the fertile phase, but only in response to photographs of their boyfriends.

Whatever is going on, women shouldn’t worry that they’re advertising their fertility status to men by way of a flushed red face. The changes in redness are related to cycle phase, but not to fertility or risk of conception.

Robot law: what happens if intelligent machines commit crimes?

I'd buy that for a dollar. Or, just steal it from you. elbragon, CC BY

The fear of powerful artificial intelligence and technology is a popular theme, as seen in films such as Ex Machina, Chappie, and the Terminator series.

And we may soon find ourselves addressing fully autonomous technology with the capacity to cause damage. While this may be some form of military wardroid or law enforcement robot, it could equally be something not created to cause harm, but which could nevertheless do so by accident or error. What then? Who is culpable and liable when a robot or artificial intelligence goes haywire? Clearly, our way of approaching this doesn’t neatly fit into society’s view of guilt and justice.

While some may choose to dismiss this as too far into the future to concern us, remember that a robot has already been arrested for buying drugs. This also ignores how quickly technology can evolve. Look at the lessons from the past – many of us still remember the world before the internet, social media, mobile technology, GPS – even phones or widely available computers. These once-dramatic innovations developed into everyday technologies which have created difficult legal challenges.

A guilty robot mind?

How quickly we take technology for granted. But we should give some thought to the legal implications. One of the functions of our legal system is to regulate the behaviour of legal persons and to punish and deter offenders. It also provides remedies for those who have suffered, or are at risk of suffering harm.

Legal persons – humans, but also companies and other organisations for the purposes of the law – are subject to rights and responsibilities. Those who design, operate, build or sell intelligent machines have legal duties – what about the machines themselves? Our mobile phone, even with Cortana or Siri attached, does not fit the conventions for a legal person. But what if the autonomous decisions of their more advanced descendents in the future cause harm or damage?

Criminal law has two important concepts. First, that liability arises when harm has been or is likely to be caused by any act or omission. Physical devices such as Google’s driverless car, for example, clearly has the potential to harm, kill or damage property. Software also has the potential to cause physical harm, but the risks may extend to less immediate forms of damage such as financial loss.

Second, criminal law often requires culpability in the offender, what is known as the “guilty mind” or mens rea – the principle being that the offence, and subsequent punishment, reflects the offender’s state of mind and role in proceedings. This generally means that deliberate actions are punished more severely than careless ones. This poses a problem, in terms of treating autonomous intelligent machines under the law: how do we demonstrate the intentions of a non-human, and how can we do this within existing criminal law principles?

Robocrime?

This isn’t a new problem – similar considerations arise in trials of corporate criminality. Some thought needs to go into when, and in what circumstances, we make the designer or manufacturer liable rather than the user. Much of our current law assumes that human operators are involved.

For example, in the context of highways, the regulatory framework assumes that there is a human driver to at least some degree. Once fully autonomous vehicles arrive, that framework will require substantial changes to address the new interactions between human and machine on the road.

As intelligent technology that by-passes direct human control becomes more advanced and more widespread, these questions of risk, fault and punishment will become more pertinent. Film and television may dwell on the most extreme examples, but the legal realities are best not left to fiction.

Boldly going into space for 1,000 days presents a series of health risks

Padalka might be keeping fit but we simply don't know what effect repeated space travel can have on our bodies. NASA/wikimedia

Russian cosmonaut Gennady Padalka, the commander of the current crew on board the International Space Station, has broken the record for the longest time spent in space with 803 days. Padalka, who is to return to Earth in September, has previously said he would like to try for 1,000 days on a future mission.

However, space travel significantly alters our bodies. While we don’t know exactly what the cumulative effect of several long journeys to space is, Padalka is at risk developing a range of health problems – including back problems, osteoporosis (brittle bones), cancer and damage to the nervous system.

Thank gravity for big guns

Living on the Earth’s surface, gravity constantly pulls our bodies downwards, keeping us firmly on the ground. Our muscles have to contract continuously to stand up against this gravitational pull or to lift objects. It causes us to get slightly shorter during waking hours. Gravity also pulls our blood down into our legs and our hearts have to work hard to pump oxygen-rich blood to our brains.

But our bodies are adapted to these conditions. In space, the lack of gravity has profound effects on the human body – and these effects are amplified the longer we stay in the low-gravity environment in space (known as microgravity). While in microgravity, astronauts will typically see their muscles waste away, their bones lose mineral density and their blood reduce in volume.

A thousand days on the ISS could have a high cost. NASA

In space, our muscles waste away simply because they are not used. Reductions in muscle size have been reported after as little as two weeks of exposure to microgravity during space shuttle missions – and significant reductions are experienced after long duration missions of around 6 months to ISS.

The muscles in our legs and torso are the most affected since they are not used as much on the ISS as they are on Earth. Astronauts don’t need to walk or stand upright against gravity. The muscular changes experienced as a result of space flight are very similar to those seen as our bodies age.

This damage occurs despite the fact that astronauts take part in up to two hours of exercise on the ISS each day, leading to significant issues once back on Earth. As a result, astronauts typically have to undergo a rigorous rehabilitation programme to help them stand up straight again.

Taller in space

Travelling to space also affects astronauts’ skeletons significantly. As gravity is not pulling them downwards, their spines lengthen up to as much as a few inches over the course of a long-duration mission to the ISS. This increase in the length of the spine is due to an increased volume of fluid in the spinal discs – fluid which is normally squeezed out over the course of the day when we are on Earth.

Do you feel taller? (Mercury astronauts in simulated weightless flight in 1958.) NASA

This effect, combined with the changes to muscle control, makes the spine less stable – leading to lower-back pain both during and after space flight. In fact, astronauts are at much greater risk of a slipped disc within the first year after they return from space.

On Earth, every time we take a step or land after a jump, our bones – especially in our legs – are loaded as a result of gravity. This helps our bones maintain an appropriate density of minerals (including calcium). Since astronauts’ bones are not loaded in this way in space, bone mineral density reduces. The exception to this is the bones of the upper body (the arms, for instance) which are used more in space and can show a slight increase in bone mineral density.

This loss of bone density leads to the bones becoming brittle, similar to people on Earth who develop osteoporosis. Research has predicted that only 50% of the loss in bone density will be restored after 9 months back on Earth.

Another problem that occurs with a lack of gravity is that the heart does not need to work as hard to pump blood to the brain. Astronauts’ bodies adapt to this by reducing the volume of blood in the body. The effects are not noticed while in space. However, when returning to Earth, astronauts’ blood is suddenly pulled back down towards their feet which leads to the brain not receiving enough oxygen-rich blood. This can lead to dizziness and astronauts are often seen to faint.

Padalka’s verdict

In general, astronauts’ bodies age at an accelerated rate in space, therefore causing significant challenges upon return to Earth. Padalka, who has been on a number of space missions since 1998, will no doubt have experienced many changes to his body. Every time he returned to Earth, his body will have recovered to some extent following a period of intense rehabilitation, but not everything will have returned to normal. The muscles that support the spine, however, are known not to recover well, even after six months of recovery after a period of disuse.

In addition to facing osteoporosis and back pain, Padalka will also be at greater risk of developing cancers and damaging his central nervous system as a result of prolonged exposure to radiation in space.

Do rats dream of the future?

Do rats dream of electric treats? Starsandspirals, CC BY-SA

Rodents, one might guess, live in the present – seeking out the best rewards they can scurry to. Indeed, the Scottish poet, Robert Burns, encapsulated this in his poem, “To a Mouse”, with the lines:

Still, thou art blest compar’d wi’ me! The present only toucheth thee: But Och! I backward cast my e’e, On prospects drear! An’ forward, tho’ I canna see, I guess an’ fear!

Legend has it that Burns wrote the poem after turning a mouse out of its home when ploughing his fields. He felt pity for it, but also envied the mouse for its inability to worry about what the future might bring. However, it seems Burns may have been wrong. New research published by our research team in eLife indicates that rodents do in fact appear to simulate the future, and they do so during sleep/rest periods.

We have known since the 1970s than neurons, called “place cells”, in a brain area called the hippocampus form an organised map of space through their spatially localised patterns of activity. Because each cell is active in a different part of a space, the population of activity from these cells provides a sort of “you are here on the map” signal to the rest of the brain connected to the hippocampus. Place cells are typically recorded in rats, but similar patterns have been observed in humans.

One dogma is that place cells can only form a map during active physical travel through a space. However, we wondered whether this assumption might be wrong. This was because a recent study found that humans with hippocampal damage struggled to imagine future scenarios. When asked to imagine lying on a beach in a tropical bay, for example, the patients described having great difficulty creating a coherent scene in their mind’s eye. We speculated that if place cells not only map space during physical exploration, but also during mental exploration of a future space, this might underlie why the patients were unable to imagine fictitious places. The patients' place cells were damaged making them unable to mentally construct imagined places.

To test this hypothesis, we placed rats on a straight track with a T-junction ahead while recording place cells from their hippocampus. Access to the junction – as well as the left and right hand arms beyond it – was prevented by a transparent barrier. One of the arms had food at the end, while the other side was empty. After observing the food the rats were put in a sleep chamber for an hour. Finally, the barrier was removed and the rats were returned to the track and allowed to run across the junction and on to the arms.

Brain activity and dreams come together in Inception. Diraen, CC BY

During the rest period, the data showed that the place cells that would later provide an internal map of the food arm were active. Cells representing the empty arm were not activated in this way. More specifically, the map was sequentially activated consistent with trajectories leading to and from the food – what we refer to as “pre-play”. This indicates that the hippocampus was simulating or preparing future paths leading to a desired goal.

So if rats are able to simulate future scenarios when resting in a sleep chamber, does this mean that the rats were dreaming of running to the food during the rest period? The truth is we don’t know. We only know humans dream because we can speak to them about their inner experiences after they wake.

We also don’t know whether the activity recorded in our experiment comes from specific periods of sleep in which dreams in humans tend to be reported (for example in REM sleep). However, the idea that such activity patterns in the hippocampus might underlie the content of dreams has been speculated on before and this is thought to have influenced the recent film Inception.

Dreaming – and rats (22:05 minutes in)

In the future it may be possible to relate the activity of place cells recorded in humans to dream content. However, technical challenges of recording enough cells make this difficult. A more tractable project for future work is to establish whether or not the pre-play is behaviourally important.

We found that the greater the interest each rat showed in the unobtainable food the more pre-play they expressed in their hippocampus. Currently this is based on evidence from just four rats. Future work with greater numbers of rats and future manipulations of the possible options of routes to a goal would help.

Whether rats dream at all remains unclear, but what is clear is that they are capable of processing relevant futures, yet to happen, during their periods of rest. Thus, rats may be more similar to us humans in their capacity to wonder about what the future holds.

The rise and demise of a super-armoured "monster worm" from ancient China

Scary-looking creature but at least it doesn't bite. Credit: Jie Yang

It was partly bald, partly covered in hair and had 15 pairs of legs, 72 spines and two antennae. It’s no wonder that worm-like creatures like Collinsium ciliosum are also known as “Hairy Collins’ Monsters”. The animal, discovered in China, lived over half a billion years ago, during the Cambrian period.

This heavily armoured creature is one of the first early animals to have developed an external skeleton specialised for self defence. It adds to a growing number of weird and wonderful fossils from this dynamic period, unravelling the mysteries of how life on Earth came to be.

Armed to the (non-existent) teeth

Collinsium was discovered in Xiaoshiba – an exceptionally well-preserved fossil site in south China. It’s part of the animal group Lobopodia: worm-like creatures with legs. Lobopodians have existed from the Cambrian (ocean-dwelling) right up to the modern day, with examples such as velvet worms (land-dwelling).

The modern day cousin of Collinisium – a velvet from Ecuador. Geoff Gallice/Flickr, CC BY

Collinsium had two antenna-like features on its head, six pairs of bristly legs and, at the rear, nine pairs of legs with tiny claws. Although Collinsium had numerous pairs of legs, they were most likely not for walking. The bristly legs were used to collect tiny floating particles of food suspended in the surrounding waters, whereas the clawed legs, with ring-like segments, helped with climbing and anchoring it on the ocean floor.

Because the flexible appendages at the front end of Collinsium filtered food, it had a very basic mouth structure. This meant that it had very few oral features, for instance, no teeth. The front section was also covered in tiny hairs, unlike the back end, which was comparatively bald – with the exception of a few small clusters of hairs around glands, known as papillae.

But perhaps the most incredible feature of Collinsium was its spines. These protective structures could be seen running along the creature’s back in rows, a total of 72 spines. Although lobopodians commonly have spines, most have significantly fewer than Collinsium. An example of this is Hallucigenia, which had two spines for each pair of legs, whereas Collinsium had up to five. Hallucigenia also differs from Collinsium in its feeding habits – Hallucigenia didn’t have the bristly, suspension-feeding limbs, as seen on Collinsium. Researchers have referred to Collinsium as “Hallucigenia on steroids”.

Reconstruction of the armoured worm. Credit: Javi er Ortega-Hernández

It also appears that the spines on Collinsium, although positioned in rows, could move individually. This meant that it could point each of its spines in different directions – an excellent defensive feature when it comes to protecting yourself from predators.

Too specialised to survive

This specialised mode of life, with extensive protective spines and distinctive limbs, came to an end for lobopodians by the middle Cambrian. It’s believed that Collinsium, alongside similar lobopodians, fitted into a palaeoecological niche during the Cambrian explosion – thriving at a time when ecological and environmental conditions were optimum for the success of this particular creature.

The extinction of Collinsium could therefore have been a result of changes to its local ecology or environment (for example, alterations to the food chain).

Unfortunately, since it’s difficult to fossilise the soft tissues of lobopodia, it is possible that palaeontologists will only ever be able to study a handful of specimens from sites of exceptional preservation, such as Xiaoshiba. Sadly, this is a common problem in palaeontology, but this certainly doesn’t stop incredible discoveries, such as Collinsium, enhancing our understanding of Earth’s dynamic history.